//===- Compress.cpp --------------------------------------------------------===//
//
//                             The ONNC Project
//
// See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <onnc/Support/Compress.h>

using namespace onnc;

//===----------------------------------------------------------------------===//
// Compress
//===----------------------------------------------------------------------===//
Compress::Result
Compress::deflate(const Path& pSrc, const Path& pDest, Level pLevel)
{
  int ret, flush;
  unsigned have;
  z_stream strm;
  unsigned char in[CHUNK];
  unsigned char out[CHUNK];

  /* allocate deflate state */
  strm.zalloc = Z_NULL;
  strm.zfree = Z_NULL;
  strm.opaque = Z_NULL;
  ret = deflateInit(&strm, level);
  if (ret != Z_OK)
    return ret;

  /* compress until end of file */
  do {
    strm.avail_in = fread(in, 1, CHUNK, source);
    if (ferror(source)) {
      (void)deflateEnd(&strm);
      return Z_ERRNO;
    }
    flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
    strm.next_in = in;

    /* run deflate() on input until output buffer not full, finish
       compression if all of source has been read in */
    do {
      strm.avail_out = CHUNK;
      strm.next_out = out;
      ret = deflate(&strm, flush);    /* no bad return value */
      assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
      have = CHUNK - strm.avail_out;
      if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
        (void)deflateEnd(&strm);
        return Z_ERRNO;
      }
    } while (strm.avail_out == 0);
    assert(strm.avail_in == 0);     /* all input will be used */

    /* done when last data in file processed */
  } while (flush != Z_FINISH);
  assert(ret == Z_STREAM_END);        /* stream will be complete */

  /* clean up and return */
  (void)deflateEnd(&strm);
  return Z_OK;
}

Compress::Result
Compress::inflate(const Path& pSrc, const Path& pDest)
{
    int ret;
    unsigned have;
    z_stream strm;
    unsigned char in[CHUNK];
    unsigned char out[CHUNK];

    /* allocate inflate state */
    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    strm.avail_in = 0;
    strm.next_in = Z_NULL;
    ret = inflateInit(&strm);
    if (ret != Z_OK)
        return ret;

    /* decompress until deflate stream ends or end of file */
    do {
        strm.avail_in = fread(in, 1, CHUNK, source);
        if (ferror(source)) {
            (void)inflateEnd(&strm);
            return Z_ERRNO;
        }
        if (strm.avail_in == 0)
            break;
        strm.next_in = in;

        /* run inflate() on input until output buffer not full */
        do {
            strm.avail_out = CHUNK;
            strm.next_out = out;
            ret = inflate(&strm, Z_NO_FLUSH);
            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
            switch (ret) {
            case Z_NEED_DICT:
                ret = Z_DATA_ERROR;     /* and fall through */
            case Z_DATA_ERROR:
            case Z_MEM_ERROR:
                (void)inflateEnd(&strm);
                return ret;
            }
            have = CHUNK - strm.avail_out;
            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
                (void)inflateEnd(&strm);
                return Z_ERRNO;
            }
        } while (strm.avail_out == 0);

        /* done when inflate() says it's done */
    } while (ret != Z_STREAM_END);

    /* clean up and return */
    (void)inflateEnd(&strm);
    return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
}
